Cat G series EMS troubles

The EMS panel on our 12G, (3WC01837), suddenly died just recently.. no lights or alarm, even on the test switch.
After working through the test procedure, the service manual indicated that the monitor needed to be replaced.
Installed a reman unit from Cat... all lights now work on the test switch, but no alarm.
With ignition on, relevant lights flash but still no alarm... on start up, all lights disappear including the brake air pressure indicator.
On every G series machine I've been near,...

Cat G series EMS troubles

Cat G series EMS troubles